According to the data of the specialized literature, the early school age is a very important not only for students‘ training from a motor point of view but also functionally. They fit perfectly into the socalled critical periods of development of motor qualities, namely the most favorable periods for the development of one or another quality which refers specifically to the age of 7-11 years. This will be taken into consideration by every teacher of physical education and all possible resources and methods will be used to influence the successful development and physical training of students. One of the main motor qualities that can and should be developed for primary school students during this period is flexibility. There are several approaches to the development of flexibility in the specialized literature; moreover, stretching exercises in the training process is considered the most effective one. This article aims to highlight the effectiveness of applying stretching exercises in the development of flexibility of the primary school students.